2007/13 – Bright (Victoria) – E.coli, Iron, Colour, Manganese, Turbidity, Taste and Odour

Bright (Victoria): E.coli
29/10/07: Bright & Wandiligong. E.coli detection (21 orgs/100ml). Additional chlorine dosed to affected
area. Retest was clear.
(North East Water Water Quality Report 2007/08)

“Coliforms are Gram-negative, non-spore-forming, rod-shaped bacteria that are capable of aerobic and facultative anaerobic growth in the presence of bile salts or other surface active agents with similar growth-inhibiting properties. They are found in large numbers in the faeces of humans and other warm-blooded animals, but many species also occur in the environment.

Thermotolerant coliforms are a sub-group of coliforms that are able to grow at 44.5 ± 0.2°C. E. coli is the most common thermotolerant coliform present in faeces and is regarded as the most specific indicator of recent faecal contamination because generally it is not capable of growth in the environment. In contrast, some other thermotolerant coliforms (including strains of Klebsiella, Citrobacter and Enterobacter) are able to grow in the environment and their presence is not necessarily related to faecal contamination. While tests for thermotolerant coliforms can be simpler than for E. coli, E. coli is considered a superior indicator for detecting faecal contamination…” ADWG 2011

Bright –  Victoria – Iron

2007/08: Bright (Victoria)  – Iron 0.83mg/L (Highest level only)

2008/09: Bright (Victoria)  – Iron 3.7mg/L (Highest level only)

Based on aesthetic considerations (precipitation of iron from solution and taste),
the concentration of iron in drinking water should not exceed 0.3 mg/L.
No health-based guideline value has been set for iron.

Iron has a taste threshold of about 0.3 mg/L in water, and becomes objectionable above 3 mg/L. High iron concentrations give water an undesirable rust-brown appearance and can cause staining of laundry and plumbing fittings, fouling of ion-exchange softeners, and blockages in irrigation systems. Growths of iron bacteria, which concentrate iron, may cause taste and odour problems and lead to pipe restrictions, blockages and corrosion. ADWG 2011

Bright  (Victoria) – Colour

2007/08: Bright (Victoria) – Colour 20 TCU (Highest Level Only)

Based on aesthetic considerations, true colour in drinking water should not exceed 15 HU.

“… Colour is generally related to organic content, and while colour derived from natural sources such as humic and fulvic acids is not a health consideration, chlorination of such water can produce a variety of chlorinated organic compounds as by-products (see Section 6.3.2 on disinfection by-products). If the colour is high at the time of disinfection, then the water should be checked for disinfection by-products. It should be noted, however, that low colour at the time of disinfection does not necessarily mean that the concentration of disinfection by-products will be low…

2008/9 – Bright (Victoria) – Manganese

2008/9 – Bright (Victoria) – Manganese 0.56mg/L (high)

Manganese: ADWG Guidelines 0.5mg/L. ADWG Aesthetic Guideline 0.1mg/L
Manganese is found in the natural environment. Manganese in drinking water above 0.1mg/L can give water an unpleasant taste and stain plumbing fixtures

Bright (Victoria) – Turbidity

5/09/10 – 16/09/10 Bright/ Wandiligong/ Porepunkah Boil Water Notice The raw water source was highly turbid due to heavy rainfall (Sept. floods). As a precaution the BWN was instated to reduce customer risk. Despite the precautionary BWN, drinking water quality remained compliant during the event.

2010/11: Bright Turbidity 8.8NTU

2011/12: Bright Turbidity 53NTU

Bushfires: In late February 2013, over 100 mm of rain fell at the head of the catchment over a short period which caused land slips and a major dirty water event. Turbidity levels of >30,000 NTU were recorded at the Bright offtake and >3,000 NTU a few days later at Wangaratta.

Chlorine-resistant pathogen reduction: Where filtration alone is used as the water treatment
process to address identified risks from Cryptosporidium and Giardia, it is essential
that filtration is optimised and consequently the target for the turbidity of water leaving
individual filters should be less than 0.2 NTU, and should not exceed 0.5 NTU at any time
Disinfection: A turbidity of less than 1 NTU is desirable at the time of disinfection with
chlorine unless a higher value can be validated in a specific context.
Aesthetic: Based on aesthetic considerations, the turbidity should not exceed 5 NTU at the
consumer’s tap.

Bright (Victoria) – Taste & Odour

27 December 2013 (15 days) – Bright, Porepunkah and Wandiligong

Taste and odour present in the Bright water supply system caused repeated customer enquiries. Testing indicated that the naturally occurring compound 2-Methylisoborneol (MIB) was present at high concentrations. The Bright WTP could not effectively remove the compound, so an alternative groundwater source was utilised to dilute the Ovens River source. A media release was issued for Bright, Porepunkah and Wandiligong residents explaining the nature of the taste and odour problem. Additional, broader MIB sampling was conducted to characterise the issue within the Ovens catchment. Powdered activated carbon dosing is an effective means of removing taste and odour compounds from water and will be part of the new Bright WTP which is due to commence construction in 2014-15.